Ultrasound Aided Adsorption of Cu (II), Ni (II) and Mn (II) from Wastewater onto Activated Carbon Developed from Melon Husk

Abstract

The three metal ions Cu (II), Ni (II), and Mn (II) were removed from plating wastewater using activated carbon made from melon husks (ACM), both in the presence and absence of ultrasonic vibrations. The effects of adsorbent dosage, contact time, and pH on the adsorption of Cu (II), Ni (II), and Mn (II) from wastewater were investigated in batch adsorption studies. A comparison of adsorption studies carried out with the aid of ultrasonic waves showed a higher uptake of heavy metal ions in the presence of ultrasonic waves than without ultrasonic vibrations. The adsorption capacity (Qm) of the activated carbon (ACM) obtained from the Langmuir isotherm was higher in the presence of ultrasonic waves. The adsorption capacity (Qm) of ACM in the presence of ultrasonic waves was 2.235 mg/g, 1.473 mg/g, and 0.985 mg/g for Cu (II), Ni (II), and Mn (II); without irradiation, the values were 1.742 mg/g, 0.704 mg/g, and 0.524 mg/g for Cu (II), Ni (II), and Mn (II) by Langmuir isotherm models. The adsorption process was irradiated with an ultrasonic wave and, without irradiation, obeyed pseudo-second-order kinetics. The adsorbents were characterized using SEM and EDS analyses. The SEM images revealed the porous structure of the adsorbent for the adsorption of Cu (II), Ni (II), and Mn (II).